I'm level 22 atm, and I have about 1k+ kills in dm_lockdown. However, the game got incredibly unstable. I accidentally fired an smg1 grenade at a huge pile of weaponry (drops from NPC's due to me camping) and it caused a MASSIVE fps issue, where it dropped to something like... 2. After that I simply did ent_remove_all weapon_smg1 hoping that it'll fix the issue... and it did. Lag disappeared, but then the game got incredibly unstable. Crashes out of nowhere without any error message. I assume it happens when I kill a NPC which used to have an SMG1 but now doesn't, due to the fact that ent_remove_all weapon_smg1.

Which gives me a suggestion - do cleanup at random times so that this wouldn't happen